Why Do Bearded Vultures Dye Their Feathers?

The bearded vulture is a force to be reckoned with. It's a fighter from birth, habitually battling its only other sibling to the death to become its parents' sole offspring. When it grows to adulthood, it weighs in at around 18 pounds, a heft that comes in handy when fighting off any other vulture that ventures within its several-hundred-kilometer territory. It scavenges the bones of other animals' kills, eating the smaller bones whole and dropping larger bones from a lofty height so they break into more manageable pieces. With all this bravado, it might be surprising to learn that the bearded vulture is the only bird known to wear cosmetics.

Bearded vultures are born with black and white feathers. But beginning around age 7, they begin finding red, iron-rich sources of soil and mud that they use to dye their white heads, necks, and breasts. It's clear to scientists that this isn't just an act of cleansing or cooling off, but an intentional aesthetic choice. "The movements in the red soils are elaborate, different than when they bathe in clear water," biologist Antoni Margalida told the National Wildlife Federation. There are a few theories as to why they gussy up with bright colors. Red is popular in the bird world, but the mostly-bone diet of bearded vultures lacks the carotenoids that give most other birds their red hues. It also may advertise skill and street smarts, since iron-rich soil is somewhat rare where the birds live and bright red plumage advertises that the wearer has knowledge of a secret cache. Learn more about these creatures with the videos below.